The yanks wanted UAT as the standard but ICAO went with 1090es.
OZ,
With all due respect, that is simply not true. US promoted UAT ( CDMA, Qualcomm hold the patents) and Europe wanted VDL-4 (TDMA and Ericsson hold the patents).
ICAO finally accepted all three, such was the politics.
There is no doubt UAT is the superior technology, but VDL-4 would have worked for aviation, and was, in fact, the first system to go into day to day use, in Scandinavia. The large scale Mediterranean trial used VDL-4.
1090ES was/is the lashup that several very large aerospace industry manufacturers promoted to the airline industry, world wide, as a cheap and easy way of avoiding fitting new equipment ----- the rest is history. Never underestimate the lobbying power of very short sighted airlines and the ATA/IATA, even as we speak, ADS-B is anything but a done deal in the US.
VDL-2 is becoming very widely used for datalinks, world wide, replacing the original ACARS. VDL-4 has been widely adopted for ground collision avoidance, including in US. The US Marines have adopted VDL-4 ( which seems odd to me) for practice range management.
Wordlwide adoption of CDMA based would have been the smartest answer, adoption of 1090ES is certainly the dumbest answer, as the US ATA has finally realised, but for the time being, they are stuck with their previous shortsightedness.
Tootle pip!!
PS:
Yes, I am opposed to mandatory ADS-B in Australia, it has never been cost/benefit justified, and the Australian preoccupation with ADS-B for collision avoidance just reveals a totally unreal estimate of the risk of collision, and the ability of ADS-B to mitigate that risk.
You realise, of course, that ADS-B IN information is NOT processed by TCAS 11.
The actual collision risk in any Australia airspace is so small that it is the statistically the equivalent of zero, except in circuit areas, where the risk is already ALARP. In VFR/vmc circuit areas, your eyeballs do not have the shortcomings of ADS-B at very short ranges.
I have no idea where you get the idea of avionics equipment turnover in airlines ( as opposed to private owners with more money than sense) where equipment generally remains as it came out of the factory, unless an AD dictates otherwise, such as the various software upgrades to TCAS 11, or regulatory change dictates.
The costs of the upgrades to Qantaslink -8s is a good example of real costs, versus the nonsense promulgated by Airservices in the early days. In fact, the Qantaslink costs were very close to the costs estimates in the FAA NPRM, and several orders of magnitude greater than CASA NPRMs.